In our studies to date we have (1) identified receptors for lactogen, insulin, gorwth hormone, and somatomedins (IGFs) in Golgi elements from rodent liver; and shown that intracellular and cell surface receptors are regulated differently. (2) Identified a unique intracellular vesicle, other than classical Golgi, enriched in hormone receptors. (3) Studied internalization into pancreatic acinar cells wherein we have shown intracellular radiolabeled insulin associated with secretory (anabolic) elements of the vacuolar system. (4) Initiated studies on the mechanism of chloroquine action. (5) Obtained evidence for the intracellular translocation (processing) of hormone. In the coming year we plan to: (1) Isolate and further characterize the unique intracellular vesicle. (2) Study factors regulating intracellular processing of hormone. (3) Determine the precise site of chloroquine action. (4) Study the internalization of glucagon and parathyroid hormone. (5) Start studies on the sequence of metabolism of internalized insulin and on the possible biological actions of internalized hormone.